The present invention relates to an entrance roller guide apparatus provided for guiding a material to be rolled, hereinafter a workpiece material, to a rolling roller for rolling such a shape steel as a channel steel or the like.
It is well known that related arts greatly influence the quality of a final product when there is torsion or roll flaw of a material to be rolled, or a difference in height between left and right flanges thereof, in a rolling work of a channel steel. Causes of these phenomena include, first, that the width of a workpiece material which has advanced to a rolling roller is larger than that of an opening portion of a roll. Second, another of the causes is due to that it is difficult to identify a deformation of the workpiece material in a grooved rolling so that channel forming becomes difficult, which is well known.
On the contrary, in view of that, when a channel material is rolled, a width of the workpiece material, or the channel material, is conventionally larger than that of the roll opening portion, the width between friction guides is narrowed so that the workpiece material is guided to grooves of rolling rolls while the material passing through between the guides is forcibly shaped.
Also, as a related art, there has been proposed an entrance guide apparatus for a rolling mill where a roughly shaped workpiece material is accurately centered and rolled to be guided to grooves of rolling rolls by a centering roller provided inside the workpiece material having a width larger than a caliber width of the rolling rolls and standing type entrance guide rollers provided outside the workpiece material (Japanese Utility Model Application Publication No. 53 (1978)-32110).
In the related arts, there occurs a problem that, when the material workpiece is shaped by squeezing by only the friction guides, since the workpiece material is guided while being forcibly shaped, a scratching flaw occurs in a final product. Prevention of such a flaw is is attempted by providing the friction guides to guide the workpiece material with a clearance of several mm between the friction guides and the workpiece material. However, there occurs a problem that biting or engaging performance of the workpiece material to the caliber deteriorates and torsion of the material is easy to occur.
Also, when positions of the friction guides are adjusted, it is possible to adjust the width of the workpiece material in left and right directions. However, as the friction guides cannot be adjusted in a vertical direction, an advancing angle to the rolling roll cannot be adjusted in the vertical direction. Accordingly, there is a problem in which it becomes difficult to effect an exact introducing guide of the material by position adjustment of the friction guides.
Also, the above proposal is for feeding a rough steel material into the grooves of the rolling rolls by using the centering roller and the entrance guide roller. As the feeding of the rough steel material to the grooves of the rolling rolls is directly effected from these rollers positioned at positions spaced from the grooves, there is a limitation in improving an accuracy of the introducing guide for the material. As a result, it becomes difficult to prevent torsion or a flaw from occurring in the rough steel material.